BUDAPEST, Hungary (AP) — Twenty positive tests, including medal winners, were among the retested doping samples from weightlifters taken at the 2008 and 2012 Olympics, the International Weightlifting Federation said on Monday.

In a statement sent to The Associated Press, the IWF said it was informed by the International Olympic Committee of 10 cases from the 2008 Beijing Games and 10 from the 2012 London Games.

It said the Beijing tests were "presumed" positives that still require B sample analyses. The 10 from London were described as confirmed positives, or "adverse analytical findings."

The IWF said the cases include medal winners but did not give any names or nationalities.

The federation said it would "proceed to the provisional suspension of the athletes as soon as the IOC procedures (are) concluded."

The 20 cases account for a large part of the 55 total positives which the IOC has reported so far, including 32 from Beijing and 23 from London. The IOC is retesting samples to catch cheats who might be competing at the Rio de Janeiro Olympics in August.

Meanwhile, Kazakhstan's Olympic committee said its athletes recorded five positives in similarly retested A samples from Beijing and London and had sent representatives to Switzerland to attend analysis of the B samples.

The athletes were not named and it was not immediately clear in which events they competed.

The Central Asian nation has faced repeated doping scandals in recent years, particularly in weightlifting and cycling.

Separately, the Russian Olympic Committee says two of its athletes' B samples came back negative. They belonged to race walker Denis Nizhegorodov and rower Alexander Kornilov.